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By L. H. Gevantman

A program for the compilation of evaluated physical and chemical numerical properties data is being pursued at the National Bureau of Standards within the Office of Standard Reference Data. This program is being sponsored by the Department of Energy and managed by the Battelle Office of Nuclear Waste Isolation in Columbus, Ohio. The intent is to assemble a reliable body of numerical properties data concerning candidate mineralogical materials in which high-level radioactive wastes are to be buried. The ready accessibility of the data to site designers and the credibility achieved through the evaluative process are designed to help assess and compare the feasibility of each candidate material for use as a disposal site. Both generic and site-specific data are to be assembled. To date, generic rock salt properties have been assembled and published by the NBS as NBS Monograph 167. Details of the effort to produce this book are discussed.

Jan 1, 1982

By Ho-Sang Sohn

The kinetic study on desulfurization of copper matte by gas bubbling was designed under the presumptions of lower FeO activity and of no slag formation, Copper matte with 59% Cu and 22.6% S in weight was oxidized at 1523K by bubbling of Ar + O2 gas through a submerged nozzle. The effects of oxygen partial pressure and flow rate of gas on the oxidation rate of matte were discussed. The desulfurization rate and the evolution rate of SO2 gas of copper matte were significantly influenced by the oxygen partial pressure, but the dependence on gas flow rate was rather complicated. The desulfurization rate and evolution rate of SO2 gas of copper matte were described by the mass transfer rate through the gas film around the rising gas bubbles. Thermodynamic correlation equations between the partial pressure of gaseous species and matte composition were incorporated to the kinetic calculation, The present model shows that the reaction path starts to transiently cross over an isobar line of PSO2 to asymptotically approach to the particular isobar line drawn in a matte composition plane of %S and %O.

Jan 1, 2003

By Byung-Su Kim

The recovery of elemental sulfur from sulfur dioxide has important implications for coal- burning power plants and nonferrous metal smelters. The thermodynamic analyses showed calcium sulfide to be suitable for recovering elemental sulfur from sulfur dioxide. At the temperatures of 1023 to 1153 K under the sulfur dioxide partial pressures of 5.0 - 60.1 kPa, elemental sulfur from sulfur dioxide was recovered by its reaction with calcium sulfide. The kinetics of this reaction were measured at the same conditions using a thermogravimetric analysis technique. This reaction scheme would be attractive if the coproduct calcium sulfate can be reduced to regenerate calcium sulfide. This is the topic of another paper. At 1073 K under the sulfur dioxide partial pressure of 25.8 kPa, 48 % of the original calcium sulfide was converted to calcium sulfate in an hour. Under the same conditions, 55 % of the regenerated calcium sulfide were converted to calcium sulfate in an hour even after third regeneration.

Jan 1, 1999

By Janusz Majta

The aim of this work is to investigate the control of microstructure evolution through variation of particular deformation parameters in the two-phase (intercritical) region. Niobium-microalloyed and low-carbon steels were investigated. A detailed examination of the factors affecting the ferrite microstructures of tested steels indicated that there were distinct advantages of finishing at temperatures in the austenite-ferrite region. The various results of deformation in the two-phase region are presented. Consequently, the influence of the most important process parameters on the microstructure evolution and mechanical response of the material is determined. The prime objective of the realized research work is the determination of relationship between the history of deformation and final product quality i.e. texture and mechanical properties. To reach the objective, the constitutive equations are proposed for modeling the effects of the hot-deformation process occurring in the austenite and austenite-ferrite region of low carbon and microalloyed steels on the mechanical properties of the resulting product. These models link advanced, finite element approaches simulating metal flow and heat transfer during hot-plastic deformation with constitutive equations describing microstructural processes and mechanical properties.

Jan 1, 2003

By A. Bilodeau

A new hydrometallurgical process for the production of refined gold and the recovery of palladium and platinum from silver anode slimes has recently been developed and installed at the, CCR Division of Noranda Inc. The process, which facilitates the production of gold of >99.99% purity in the face of increasing palladium receipts comprises; leaching silver anode slimes with hydrochloric acid and hydrogen peroxide at 95°C to solubilize gold, palladium, platinum and base metals while simultaneously rejecting silver as insoluble silver chloride; precipitating gold from the leach solu¬tion with sulphur dioxide gas in two stages to produce a first-stage high purity gold product and a second stage impure gold which is recycled to the leach; washing, melting and casting of the pure gold; precipitation of a palladium-platinum concentrate from the gold-free solution by reduction with sodium formate at pH 4 and 95°C; and neutralization of the palladium precipitation effluent to pH 10 with lime. The results of laboratory and pilot plant studies leading to the adop¬tion of this process are discussed, and data are presented for each of the unit operations. Details of the engineering of the commercial plant are given, and plant start-up experience is described.

Jan 1, 1987

By Xianzhong Hu, Qingbo Yu, Qin Qin

"Oxy-fuel combustion is one promising option among different CO2 capture technologies. The object of this work is to show the effect of CO2 dilution on the laminar flame speed, flame structure and reaction pathway for methane oxidation at O2/CO2 atmosphere. In this paper, kinetic simulations were made using CHEMKIN with GRI-Mech 3.0 mechanism, which was validated by experimental data of laminar flame speeds. The reaction pathway of CH4/O2/CO2 mixture was derived from reaction flow analysis. Results showed that CO2 decreased the flame speeds, lowed concentration of major intermediates and increased flame thickness. The major chemical pathways of CH4 to CO2 have not changed at O2/CO2 atmosphere comparing with O2/N2 atmosphere, but contributions to major intermediates formation from each related elementary reaction have changed a lot. In addition, the secondary chemical pathways of CH3 oxidation became different at O2/CO2 atmosphere.IntroductionNowadays, as the global economy is developing fast and the pollutant levels (especially global warming gases) are increasing, a lot of researches are focusing on new technologies which can cut greenhouse gas emissions [1]. New technologies have been developed, such as high Mild combustion, flameless combustion and Integrated Gasification Combined Cycle (IGCC) technology. Oxy-fuel combustion using carbon dioxide as dilution of oxygen is considered as a promising approach for reducing CO2 emission. The properties of CO2 in flue gas are different from N2 in air. On one side, the transport, thermal and radiative properties of CO2 are different from N2 in air. On the other side, CO2 is not inert but directly participates in chemical reactions and recent researches [2-5] also present the chemical effects of CO2 on oxy-combustion. For these differences above, the characteristics of oxy-combustion are not alike with traditional combustion. It is necessary to develop the investigation of oxy-combustion.In all combustion processes, laminar flame speed is an important parameter, which links to combustion behavior. Analysis of this parameter can provide a better understanding of the effect of CO2 dilution in the process of oxy-combustion. Several investigations of laminar flame speeds of oxy-fuel flame have been improved, including experimental measurements and numerical computations. A.A.Konnov et al. measured the flame speeds of oxy-methane and oxy-ethane mixture using the heat flux method with a flat burner [6-8]. V. Ratna Kishore et al. used heat flux method to measure the adiabatic laminar flame speeds of hydrogen [9] and H2/CO mixture [10]. Adiabatic laminar flame speeds of hydrogen in O2/CO2 atmosphere are much smaller than in O2/N2 or in O2/Ar. The burning velocity of H2/CO mixture decreased with increase in CO2 content in mixture. Jeongseog Oh et al. [11] used Bunsen flame to measure the laminar flame speeds of premixed oxy-methane mixture with angle methods in atmospheric condition (300k, 1atm). The results were SL=29.1cm/s and SL=29.5cm/s respectively derived from oxy-methane from CH* images and Schlieren photos."

Jan 1, 2014

By B. J. Jody

At Argonne National Laboratory, we have been developing a potentially economical process to recycle automobile shredder residue (ASR). We identified three potentially marketable materials that can be recovered from ASR and developed technologies to recover and upgrade these materials. We built and tested a field-demonstration plant for recycling polyurethane foam and produced about 2,000 lb (907 kg) of recycled foam. Several 300-lb (I36-kg) samples were sent for evaluation and were found to be of marketable quality. We are also preparing for a large-scale test in which about 200 tons (181 tonnes) of ASR-derived fines «0.25 in. [<0.62 cm]) will be used as a raw material in cement making. A major cement company has evaluated small samples of fines prepared in the laboratory and found that they meet its requirements as a substitute for iron ore or mill scale. We also produced about 50 lb (23 kg) of recycled acrylonitrile butadiene styrene (ABS) from obsolete automobiles and found that it has properties that could be readily upgraded to meet the specifications of the automotive industry. In this paper, we briefly discuss the process as a whole and summarize the results obtained from the field work on foam and fines recycling.

Jan 1, 1996

By Peter C. Hayes

"The high temperature reduction of solids through the use of reactive gas atmospheres has application in a wide range of industrially important processes. Whilst significant advances have been made in understanding and describing these processes, some key aspects of the chemical reactions and reaction mechanisms operating in these systems, for example, the transformation from metal oxide to metal, remain poorly understood. A number of different product morphologies have been identified in these reaction systems and the reaction rates have been shown to be critically dependent on the product structure.Theoretical examination of the elementary process steps taking place in the region of the gas/metal/metal oxide interface, combined with electron microscope studies of the resultant product microstructures, have enabled the key process and material variables responsible for the development of the various product morphologies to be identified. By considering i) established criteria for the stability of moving interfaces in a thermodynamic potential gradient, ii) the relative rates of chemical reactions on the oxide and metal surfaces, and iii) key process phenomena and physico-chemical properties of the solid phases, the mechanisms and conditions for the formation of various product morphologies are identified. Interestingly the analysis points to direct analogies between these phase transformations and, the phenomena and microstructures observed in metal solidification, and the potential to develop generic models of these fluid/solid reaction systems."

Jan 1, 2013

By R. P. King

The essential features of an image analysis system for the measurement of mineral liberation are described. Good procedures for image acquisition and image processing prior to image analysis are defined. The basic stereological methods for the measurement of volume fraction, surface area per unit volume, particle size distribution and liberation spectra are given. The appropriate methods for fractal correction when measuring perimeters of irregular features and for frame correction when measuring linear intercepts are developed. Practically useful and accurate procedures for the stereological correction of particle size and liberation distribution methods are given.

Jan 1, 1995

By David Ellis

The next generation of Reusable Launch Vehicle (RLV) will utilize regeneratively cooled combustion chamber liners in the engines. The current design calls for using a new Cu-8 at. % Cr-4 at. % Nb (Cu-8 Cr-4 Nb) alloy for the liners. Work is ongoing to characterize the thermophysical and mechanical properties of the alloy from - 253 to 800°C, the temperature range to which the alloy will be subjected during service. The alloy has been commercially produced in quantity for NASA. The powder size has been characterized and the microstructure examined. The powder was extruded into bar using a commercial extrusion press. In addition, samples have been hot isostatically pressed (HIPed) at NASA Glenn Research Center. Both processing methods produced fully consolidated material. Transmission electron microscopy (TEM) revealed highly faulted Cr2Nb and some elemental precipitates. Cryogenic tensile testing showed the extruded specimens had significantly higher strengths than NARloy-Z (Cu-3 wt % Ag-0.5 wt % Zr) even after being subjected to a simulated braze cycle. The Young&apos;s moduli (Cu-8 Cr-4 Nb) were lower than NARloy-Z. The lower moduli is highly beneficial for reducing thermally induced stresses in rocket engine combustion chamber liners and similar applications.

Jan 1, 1999

By Jonkion M. Font

Due to the known disadvantages of the use of iron silicate slag in the nickel converting stage, i.e., high metal losses, high magnetite content, and low fixation of impurities in the slag, the development of the new proposed "ferrous calcium silicate slag" for smelting and converting processes of nickel is very promising. Hence, considering the successful experimental results of using CaO base slag for the nickel smelting process, a study based on a detailed comparison for the phase equilibrium, and the minor elements distribution between the Ni3S2-FeS matte with either FeOx-CaO or FeOX-Si02 base slag was investigated. The main results are summarized as: no difference in the nickel losses between both slags was found at high nickel content in the matte, and the fractional distribution analysis for arsenic and antimony pointed out their preferential fixation in the calcium ferrite slag rather than in the iron silicate slag. Considering the energy and pollution issues, the technical feasibility of using calcium ferrite slag in a converting process of the Bessemer matte will have a prominent future for the nickel industry.

Jan 1, 2003

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Yuzhe Zhang, Matthew Andriese, Jiann-Yang Hwang, Guanghui Li, Zhiwei Peng, Tao Jiang

The microwave power absorption characteristics of iron oxides, including Fe2O3, Fe3O4 and Fe0.925O, have been studied by determining dielectric loss and magnetic loss distributions in 0.05-m-thick oxide slabs irradiated with 1.2-kW, 2.45-GHz microwaves. The results reveal that the dielectric loss is the main factor contributing to microwave absorption in Fe2O3 and Fe0.925O, while the magnetic loss dominates the power absorption in Fe3O4 below its Curie point. Uneven power distributions are observed in the slabs and this phenomenon becomes even worse at high temperatures at which the permittivity increases significantly. Quantification of power absorption in the oxides is of great importance for efficient and uniform microwave heating

Jan 1, 2015

By Liang Li

Thermodynamic analysis and experiments were conducted in order to verify the feasibility of preparing crude titanium tetrachloride (TiCl4) via the carbochlorination of low-grade titanium slag in molten salt. Titanium slag, assaying 74.6 wt% TiO2 with high calcium and magnesium oxide impurities, was treated by an optimized carbochlorination process in NaCl molten salt. These impurities in the titanium slag were chloridized simultaneously, and chlorination products FeCl2, MnCl2, MgCl2, CaCl2 and CrCl3 were collected in the furnace slag. XRD and SEM/ EDS analysis of residue shown that SiO2 and Al2O3 in titanium slag were difficult to chlorinate completely. Theoretical calculations and industrial-scale experimental studies reveal the content of TiCl4 in the products was more than 98.8 wt% and thus proved the feasibility of utilizing low-grade titanium slag for TiCl4 preparation by molten salt chlorination technology.

By René Bustamante

The subject of this paper is a comparative evaluation of different copper smelting gas cooling techniques, using "productivity and quality" criteria. The first section presents a brief description of the operation of the radiant and the evaporative cooling systems, focusing on the differences between each other, in particular regarding. a) mass and energy balances; b) gas flow, temperature and composition; c) dust concentration and recovery. This section includes a brief discussion of the "client-server chain", i.e. the links between the cooling equipment and the down-and up-stream operations. More in particular, the up-stream server relationship impacts on the operating stability of the furnace, and in turn on furnace down-time and Cu production losses; and the down-stream client relationship affects the operation of the electrostatic precipitators, in terms of workload and cost of handling larger quantities of dust of a given dust size The second section deals with the development of indexes to measure and compare value added through the "utilization, productivity and quality" that can be expected of both cooling methods at the physical and economic levels, and the impact on the overall smelter productivity and the final cost composition of copper. The final section presents the results and includes a discussion of the comparative advantages and disadvantages of both cooling systems.

Jan 1, 1999

By Manoj Kumar, Vinay Kumar, Nikhil Dhawan, Manish Wadhwa

"Electronic waste (e-waste) is a collective name given to discarded electronic devices such as Television, Cellular Phones and Personal Computers. Among the heterogeneous metals present in the e-waste are the base metals: copper, aluminium, nickel, tin, zinc, iron and precious metals: gold, silver, palladium, platinum apart from several hazardous and halogens metals. Hence there is a need to recover these metals from electronic scrap by recycling and then re-use, which can meet large amount of metals demand. Hydrometallurgical processing was employed for the recovery of metals from television printed circuit board (TV PCB). Different lixiviants such as hydrochloric acid, Sulphuric acid, and nitric acid were used to understand the dissolution behavior of copper, iron and lead present in the TV PCB. Effect of increasing concentration of nitric acid was also studied. Selective recovery of tin over 95% in the form of tin oxide was precipitated. The precipitated tin oxide was identified by X-ray diffraction technique. Tin oxide of purity more than 99.9% was obtained.IntroductionThe electrical and electronic industries comprising computers, television, mobiles, etc, which are manufactured utilizing printed circuit, boards, capacitors, resistance, soldering material etc. During production, at the end-of service life and degradation due to the advanced version with latest features generate valuable metallic and non-metallic constituents. European Union Council on waste electrical and electronic equipment (WEEE) has classified these into different categories as listed in Table 1 [Streicher-Porte et al., 2005]. Among these the information technology, telecommunications and consumer equipment constitute electronic waste (e-waste) [EC, 2002]. Almost all e-waste consists of an integrated part of printed circuit boards which is a valuable source of several metals such as copper, tin, lead, aluminium, iron, silver, gold, platinum etc. [Relay et al., 1990]."

Jan 1, 2008

By Sungdon Kim, Chuljoo Kim, Joonsoo Kim, Hosung Yoon

"This study was performed to establish the optimum leaching condition through the experiments for the oxidized roasting followed by leaching of fluorocarbonate rare earth mineral (bastnasite) using sulfuric acid, and to establish the optimum condition for the recovery of cerium by ion- sieve method from the leached solution of bastnasite. The optimum conditions for the sulfuric acid leaching by the oxidizing roasting of bastnasite concentrates are that the roasting temperature is 550 -600 °C, the roasting time is 2 hrs, the concentration of sulfuric acid is 6N, the leaching temperature is S0°C and the leaching time is 3 hrs. At this time, the leaching yield of total rare earth oxides in the leaching of bastnasite concentrates is about 91%. When cerium is recovered by ion-sieve method from the solution obtained by the sulfuric acid leaching of the roasted bastnasite, the optimum conditions are that the TREO(total rare earth oxide) of leached solution is below 70 g/l, the flow rate of leached solution is 9.6 ml/min and the ratio of height to diameter of resin packed in column is above 9. In these conditions, the recovery of cerium of yield 85% and purity 96% is possible.IntroductionThe rare earths are generally called to Lanthanides, which are totally 17 elements including Scandium of atomic number 21 and Yttrium of atomic number 39 in addition to 1 S elements from Lanthanum of atomic number 57 to Lutetium of atomic number 71. Since the separation to each element is very difficult because of their similar chemical properties, the rare earths were used as the mixed rare earths and the mischmetal without separating to each element. However, the high purity rare earths are recently produced commercially to each element so that they are used as the materials for high tech. industry such as electric and electronic materials, catalysts, optical materials, special alloy and 8Uperconductive materials, and their consumption is rapidly increasing. Therefore, the purpose of this study is firstly to prepare leached solution by using the series of process of the oxidation-roasting and leaching by sulfuric acid. Next, second purpose is the separation and recovery of cerium by ion-sieve method."

Jan 1, 1998

By Anna Wasilkowska

The study concentrates on the effects exerted by microstructure, deformation history and uniaxial stress conditions (temperature, stress state, strain rate) on the mechanical properties offerritic TRIP-aided steels for automotive applications. In low-alloyed TRIP-steels it is quite difficult to separate the effect of the austenite to martensite phase transformation from the influence of the ferritic matrix contributing to the yield stress and uniform elongation. Investigation of transformation kinetics of retained austenite as a function of the deformation temperature show that using the parameter k to characterize the retained austenite stability allows to identify regious of different temperature sensitivity separated by a transition temperature of 10±5°C. The observed low strain-rate sensitivity of the flow stress is an intrinsic property of the ferritix matrix and points to defomtation governed by slip. The ultimate tensile strength is much stronger affected by temperature than the yield stress. The influence of the temperature on the elongation is complex, because of the heating of the specimens by 60-l20°C at moderate and high strain rates. The increase of the total strain can be understood in terms of thermal softening of the ferrite. On the other hand, the steep increase of the stress during dynamic testing is an effect of accommodated elastic and plastic strains in the matrix. The strain- hardening exponent is dependent on the conditions imposed during testing. The martensite transfomtation rate is lower and the critical stress for martensite nucleation is much higher under compression compared to tensile loading. In secondary tensile tests, the yield stress increases steeply, and the ultimate tensile strength and the total elongation depend linearly on the amount of pre-straining. The results confirm that in the range of 8=10-4 s-l the TRIP-effect governs room temperature plasticity. Keywords: TRIP-steels, mechanical properties, strain rate sensitivity, temperature sensitivity, austenite stability

Jan 1, 2003

By William E. Torres

The Southern Peru Limited smelter, in Ilo, operates two reverberatory furnaces, seven Peirce-Smith converters, one Teniente Converter, two casting wheels and a single contact acid plant. The Teniente Converter was commissioned in August 1995 and was designed to smelt 744 dry metric tons (820 dry short tons) of concentrate per day. The process off-gas is collected in a water-cooled hood, cooled in a spray chamber, and cleaned in a Joy electrostatic precipitator for further treatment in the Acid Plant. This paper presents the current Teniente Converter operating practices and control philosophy. Relevant improvements and modifications to achieve a 379 day campaign without tuyere replacement and a daily average smelting rate of 862 dry metric tons (940 dry short tons) of concentrate are discussed.

Jan 1, 1998